The present disclosure relates to the subject matter disclosed in application No. 199 59 960.0 of Dec. 13, 1999, the entire specification of which is incorporated herein by reference.
The invention relates to a lathe comprising a machine frame, a first workpiece spindle with an approximately vertically aligned first spindle axis and a first workpiece holder, a first carriage system for moving the first workpiece spindle relative to the machine frame transversely to its spindle axis and in the direction of the spindle axis, a first tool carrier for machining a workpiece received in the first workpiece spindle, a second workpiece spindle with an approximately vertically aligned second spindle axis and a second workpiece holder arranged facing the first workpiece holder, a second carriage system for moving the second workpiece spindle relative to the machine frame transversely to its spindle axis, a second tool carrier for machining the workpiece received in the second workpiece spindle, the first workpiece spindle and the second workpiece spindle being adapted to be brought into a transfer position by driving the carriage systems transversely to the respective spindle axes and the workpiece being adapted to be transferred directly from one of the workpiece spindles to the other one of the workpiece spindles in the transfer position.
Such a lathe is known, for example, from DE-A-197 53 898.
However, in such lathes the machine frame is of complicated design.
The object underlying the invention is, therefore, to so improve a lathe of the generic kind that the machine frame can be manufactured in as simple and cost-efficient a way as possible.
This object is accomplished in a lathe of the kind described at the outset, in accordance with the invention, in that the machine frame comprises a first machine bed and a second machine bed constituting an assembly separate from the first machine bed, and in that the first carriage system is guided solely on the first machine bed, and the second carriage system is guided solely on the second machine bed.
The advantage of the solution according to the invention is to be seen in that the lathe according to the invention can be manufactured in the form of two modules, namely, on the one hand, a module comprising the first machine bed with the first carriage system, and, on the other hand, a module comprising the second machine bed with the second carriage system, and, therefore, there is no need, for example, to move a carriage from one module to the other.
This enables considerable rationalization of the manufacture of the lathe according to the invention.
So far, details have not been given of the connection between the first machine bed and the second machine bed. In principle, it is conceivable to set up the first machine bed and the second machine bed alongside each other in the desired alignment and to fix these relative to each other.
It is, for example, conceivable to connect the first machine bed and the second machine bed directly to each other, and this connection can also be a vibration-absorbing connection.
However, in order to make consistent use of the inventive division of the lathe into two modules, and, in particular, also for the question of uncoupling the workpiece spindles during the machining, it is particularly advantageous for the first machine bed and the second machine bed to be arranged in a non-contacting way and free from any direct connection with each other, so that, for example, vibrations and thermal influences between the machine beds are not directly transferred.
A particularly suitable way of setting up the first and second machine beds relative to each other provides for the first and second machine beds to be seated on a common underframe.
Such a common underframe can be used to position the machine beds relative to each other, and it is conceivable to also connect the machine beds to each other or to arrange these so that they are not in contact with each other.
It is, however, particularly advantageous for the first and second machine beds to be positioned relative to each other solely via the underframe.
Details of the design of the machine beds themselves were not given in the above explanation of the individual claims. An advantageous embodiment provides for the first machine bed to comprise a first carriage bed extending transversely to the first spindle axis, with the first carriage system being drivable along the first carriage bed.
Moreover, it is in the same way advantageous for the second machine bed to comprise a second carriage bed extending transversely to the second spindle axis, with the second carriage system being drivable along the second carriage bed.
Many different solutions are conceivable for the alignment of the first machine bed and the second machine bed relative to each other.
For example, it is conceivable to arrange the machine beds relative to each other such that the first carriage guiding direction and the second carriage guiding direction extend parallel to each other.
Alternatively, it is conceivable to arrange the first carriage guiding direction and the second carriage guiding direction such that the carriage guiding directions projected onto a horizontal plane include an angle with each other in this horizontal plane.
This angle may be smaller than 180xc2x0 and go up to an angle of approximately 90xc2x0.
In principle, with such a conception of the machine beds, it would be adequate to arrange these such that the carriage beds come so close to each other that the workpiece spindles arranged on the respective carriage systems can be brought into the transfer position.
It has, however, proven particularly advantageous for the stability and precision of the lathe for the first carriage bed and the second carriage bed to be arranged overlapping each other so that the workpiece spindles do not have to be arranged on the carriage systems such that in the transfer position they are arranged in the direction transverse to the respective spindle axis at the side of the respective carriage bed.
In principle, it is conceivable to arrange the carriage beds so that they overlap each other over considerable partial areas thereof.
A solution which is advantageous as regards sufficiently compact design and uncoupling of the machining operations provides for the carriage beds to be arranged so as to overlap each other with end areas thereof that face each other.
So far, details have not been given of the arrangement of the tool carriers relative to the machine beds. An advantageous embodiment provides for the first machine bed to comprise a tool carrier bed.
This tool carrier bed can be optionally arranged relative to the carriage bed of the first machine bed. An advantageous solution provides for the tool carrier bed to be arranged on a side of the first carriage bed facing a stand area of the machine bed.
It is particularly suitable for the tool carrier bed to form a foot of the first machine bed, and for the foot to carry the first carriage bed.
In the same way, it is expedient for the second machine bed to comprise a tool carrier bed.
It is preferably provided for the tool carrier bed to be arranged on a side of the second carriage bed facing away from a stand area of the second machine bed.
A particularly suitable solution provides for the second carriage bed to carry the tool carrier bed.
Further details of the arrangement of the tool carriers were not given in the above explanation of the individual embodiments. An advantageous embodiment provides for the tool carrier bed to carry a tool carrier arranged stationarily relative to the tool carrier bed, and a tool turret is also to be understood as such a stationary tool carrier.
A further alternative solution for such a stationary tool carrier provides for it to comprise a tool spindle for driven tools.
However, a prerequisite for such a stationary tool carrier is that the workpiece spindle cooperating with it be movable not only transversely to the spindle axis, but also in the direction of the spindle axis so as to be able to expediently carry out the machining of the workpiece.
Alternatively to provision of a stationary tool carrier, it is provided for the tool carrier bed to form a bed for a tool carrier guiding system.
In the simplest case, such a tool carrier guiding system can be designed so as to provide a movability of the tool carrier in the direction of the spindle axis, in particular, when the workpiece spindle is guided by the corresponding carriage system such that it is not movable in the direction of its spindle axis relative to the machine frame.
To enable more complex machinings, in particular, a finishing of workpieces, it is preferably provided for the tool carrier guiding system to provide for a movement of the tool carrier transversely to the spindle axis and also transversely to the carriage guiding direction of the carriage system carrying the workpiece spindle in a direction transverse to the spindle axis.
Such a movability of the tool carrier is usually referred to as Y-axis.
Moreover, it is advantageous for the tool carrier guiding system to provide for a rotation of the tool carrier about an axis extending transversely to the spindle axis, a so-called B-axis. In this case, in particular, complex milling operations can be carried out on the workpiece.
In the lathe according to the invention it is preferably provided for the first workpiece spindle to provide a suspended workpiece holder so that, in particular, with the first workpiece spindle owing to the movability thereof in the direction parallel to the spindle axis by means of the first carriage system, it is possible to receive workpieces in a position provided therefor from a workpiece feed device or to deposit finished workpieces on a workpiece transportation device.
In the same way, the second workpiece spindle is preferablyxe2x80x94at least in the simplest case of such a lathe according to the inventionxe2x80x94not movable in the direction of its spindle axis, but drivable transversely to the spindle axis into a position in which either a workpiece is removed or a blank workpiece is inserted.
With use of a tool carrier guiding system according to the invention, the tool carrier can be designed in many different ways. One possibility provides for it to comprise a housing on which a rotatable tool turret head is arranged.
Another solution provides for a tool spindle for a rotatingly driven tool to be arranged stationarily on the housing.
It is, however, also conceivable to arrange both a rotatable tool turret head and a tool spindle on the housing.
In this case, the axis of rotation of the tool turret head and the axis about which the tool inserted into the tool spindle rotates are preferably aligned parallel to each other.
An alternative solution thereto provides for a tool turret head to be arranged on each of opposite sides on the housing, with the tool turret heads preferably being rotatable independently of each other.
Further features and advantages of the invention are the subject of the following description and the drawings of an embodiment.